It really is -- I'm tempted to order it from the link:
http://www.ukquad.com/ "Original British Quad Movie Posters"
I don't remember this poster from the U.S. release -- it might have been only in British theaters.
Besides the fact that it was a great movie, I learned a valuable lifetime lesson when I went to see "Red Dawn" for the first time way back when (and is the reason I remember it so vividly).
It was my first real date with a young lady, and I chose this flick. I loved it, but she was rather less impressed. It's been tearjerkers in such situations for old Cad ever since...